.TH SLAPD-CONFIG 5 "RELEASEDATE" "OpenLDAP LDVERSION"
.\" Copyright 1998-2024 The OpenLDAP Foundation All Rights Reserved.
.\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
.\" $OpenLDAP$
.SH NAME
slapd\-config \- configuration backend to slapd
.SH SYNOPSIS
ETCDIR/slapd.d
.SH DESCRIPTION
The
.B config
backend manages all of the configuration information for the
.BR slapd (8)
daemon.  This configuration information is also used by the SLAPD tools
.BR slapacl (8),
.BR slapadd (8),
.BR slapauth (8),
.BR slapcat (8),
.BR slapdn (8),
.BR slapindex (8),
.BR slapmodify (8),
and
.BR slaptest (8).
.LP
The
.B config
backend is backward compatible with the older
.BR slapd.conf (5)
file but provides the ability to change the configuration dynamically
at runtime. If slapd is run with only a
.B slapd.conf
file dynamic changes will be allowed but they will not persist across
a server restart. Dynamic changes are only saved when slapd is running
from a
.B slapd.d
configuration directory.
.LP

Unlike other backends, there can only be one instance of the
.B config
backend, and most of its structure is predefined. The root of the
database is hardcoded to
.B "cn=config"
and this root entry contains
global settings for slapd. Multiple child entries underneath the
root entry are used to carry various other settings:
.RS
.TP
.B cn=Module
dynamically loaded modules
.TP
.B cn=Schema
schema definitions
.TP
.B olcBackend=xxx
backend-specific settings
.TP
.B olcDatabase=xxx
database-specific settings
.RE

The
.B cn=Module
entries will only appear in configurations where slapd
was built with support for dynamically loaded modules. There can be
multiple entries, one for each configured module path. Within each
entry there will be values recorded for each module loaded on a
given path. These entries have no children.

The
.B cn=Schema
entry contains all of the hardcoded schema elements.
The children of this entry contain all user-defined schema elements.
In schema that were loaded from include files, the child entry will
be named after the include file from which the schema was loaded.
Typically the first child in this subtree will be
.BR cn=core,cn=schema,cn=config .

.B olcBackend
entries are for storing settings specific to a single
backend type (and thus global to all database instances of that type).
At present, only back-mdb implements any options of this type, so this
setting is not needed for any other backends.

.B olcDatabase
entries store settings specific to a single database
instance. These entries may have
.B olcOverlay
child entries corresponding
to any overlays configured on the database. The olcDatabase and
olcOverlay entries may also have miscellaneous child entries for
other settings as needed. There are two special database entries
that are predefined \- one is an entry for the config database itself,
and the other is for the "frontend" database. Settings in the
frontend database are inherited by the other databases, unless
they are explicitly overridden in a specific database.
.LP
The specific configuration options available are discussed below in the
Global Configuration Options, General Backend Options, and General Database
Options. Options are set by defining LDAP attributes with specific values.
In general the names of the LDAP attributes are the same as the corresponding
.B slapd.conf
keyword, with an "olc" prefix added on.

The parser for many of these attributes is the same as used for parsing
the slapd.conf keywords. As such, slapd.conf keywords that allow multiple
items to be specified on one line, separated by whitespace, will allow
multiple items to be specified in one attribute value. However, when
reading the attribute via LDAP, the items will be returned as individual
attribute values.

Backend-specific options are discussed in the
.B slapd\-<backend>(5)
manual pages.  Refer to the "OpenLDAP Administrator's Guide" for more
details on configuring slapd.
.SH GLOBAL CONFIGURATION OPTIONS
Options described in this section apply to the server as a whole.
Arguments that should be replaced by 
actual text are shown in brackets <>.

These options may only be specified in the
.B cn=config
entry. This entry must have an objectClass of
.BR olcGlobal .

.TP
.B olcAllows: <features>
Specify a set of features to allow (default none).
.B bind_v2
allows acceptance of LDAPv2 bind requests.  Note that
.BR slapd (8)
does not truly implement LDAPv2 (RFC 1777), now Historic (RFC 3494).
.B bind_anon_cred
allows anonymous bind when credentials are not empty (e.g.
when DN is empty).
.B bind_anon_dn
allows unauthenticated (anonymous) bind when DN is not empty.
.B update_anon
allows unauthenticated (anonymous) update operations to be processed
(subject to access controls and other administrative limits).
.B proxy_authz_anon
allows unauthenticated (anonymous) proxy authorization control to be processed
(subject to access controls, authorization and other administrative limits).
.TP
.B olcArgsFile: <filename>
The (absolute) name of a file that will hold the 
.B slapd
server's command line (program name and options).
.TP
.B olcAttributeOptions: <option-name>...
Define tagging attribute options or option tag/range prefixes.
Options must not end with `\-', prefixes must end with `\-'.
The `lang\-' prefix is predefined.
If you use the
.B olcAttributeOptions
directive, `lang\-' will no longer be defined and you must specify it
explicitly if you want it defined.

An attribute description with a tagging option is a subtype of that
attribute description without the option.
Except for that, options defined this way have no special semantics.
Prefixes defined this way work like the `lang\-' options:
They define a prefix for tagging options starting with the prefix.
That is, if you define the prefix `x\-foo\-', you can use the option
`x\-foo\-bar'.
Furthermore, in a search or compare, a prefix or range name (with
a trailing `\-') matches all options starting with that name, as well
as the option with the range name sans the trailing `\-'.
That is, `x\-foo\-bar\-' matches `x\-foo\-bar' and `x\-foo\-bar\-baz'.

RFC 4520 reserves options beginning with `x\-' for private experiments.
Other options should be registered with IANA, see RFC 4520 section 3.5.
OpenLDAP also has the `binary' option built in, but this is a transfer
option, not a tagging option.
.TP
.B olcAuthIDRewrite: <rewrite\-rule>
Used by the authentication framework to convert simple user names
to an LDAP DN used for authorization purposes.
Its purpose is analogous to that of
.BR olcAuthzRegexp
(see below).
The
.B rewrite\-rule
is a set of rules analogous to those described in
.BR slapo\-rwm (5)
for data rewriting (after stripping the \fIrwm\-\fP prefix).
.B olcAuthIDRewrite
and
.B olcAuthzRegexp
should not be intermixed.
.TP
.B olcAuthzPolicy: <policy>
Used to specify which rules to use for Proxy Authorization.  Proxy
authorization allows a client to authenticate to the server using one
user's credentials, but specify a different identity to use for authorization
and access control purposes. It essentially allows user A to login as user
B, using user A's password.
The
.B none
flag disables proxy authorization. This is the default setting.
The
.B from
flag will use rules in the
.I authzFrom
attribute of the authorization DN.
The
.B to
flag will use rules in the
.I authzTo
attribute of the authentication DN.
The
.B any
flag, an alias for the deprecated value of
.BR both ,
will allow any of the above, whatever succeeds first (checked in
.BR to ,
.B from
sequence.
The
.B all
flag requires both authorizations to succeed.
.LP
.RS
The rules are mechanisms to specify which identities are allowed 
to perform proxy authorization.
The
.I authzFrom
attribute in an entry specifies which other users
are allowed to proxy login to this entry. The
.I authzTo
attribute in
an entry specifies which other users this user can authorize as.  Use of
.I authzTo
rules can be easily
abused if users are allowed to write arbitrary values to this attribute.
In general the
.I authzTo
attribute must be protected with ACLs such that
only privileged users can modify it.
The value of
.I authzFrom
and
.I authzTo
describes an 
.B identity 
or a set of identities; it can take five forms:
.RS
.TP
.B ldap:///<base>??[<scope>]?<filter>
.RE
.RS
.B dn[.<dnstyle>]:<pattern>
.RE
.RS
.B u[.<mech>[<realm>]]:<pattern>
.RE
.RS
.B group[/objectClass[/attributeType]]:<pattern>
.RE
.RS
.B <pattern>
.RE
.RS

.B <dnstyle>:={exact|onelevel|children|subtree|regex}

.RE
The first form is a valid LDAP
.B URI
where the 
.IR <host>:<port> ,
the
.I <attrs>
and the
.I <extensions>
portions must be absent, so that the search occurs locally on either
.I authzFrom
or 
.IR authzTo .

.LP
The second form is a 
.BR DN ,
with the optional style modifiers
.IR exact ,
.IR onelevel ,
.IR children ,
and
.I subtree
for exact, onelevel, children and subtree matches, which cause 
.I <pattern>
to be normalized according to the DN normalization rules, or the special
.I regex
style, which causes the
.I <pattern>
to be treated as a POSIX (''extended'') regular expression, as
discussed in
.BR regex (7)
and/or
.BR re_format (7).
A pattern of
.I *
means any non-anonymous DN.

.LP
The third form is a SASL
.BR id ,
with the optional fields
.I <mech>
and
.I <realm>
that allow to specify a SASL
.BR mechanism ,
and eventually a SASL
.BR realm ,
for those mechanisms that support one.
The need to allow the specification of a mechanism is still debated, 
and users are strongly discouraged to rely on this possibility.

.LP
The fourth form is a group specification.
It consists of the keyword
.BR group ,
optionally followed by the specification of the group
.B objectClass
and
.BR attributeType .
The
.B objectClass
defaults to
.IR groupOfNames .
The
.B attributeType
defaults to
.IR member .
The group with DN
.B <pattern>
is searched with base scope, filtered on the specified
.BR objectClass .
The values of the resulting
.B attributeType
are searched for the asserted DN.

.LP
The fifth form is provided for backwards compatibility.  If no identity
type is provided, i.e. only
.B <pattern>
is present, an
.I exact DN
is assumed; as a consequence, 
.B <pattern>
is subjected to DN normalization.

.LP
Since the interpretation of
.I authzFrom
and
.I authzTo
can impact security, users are strongly encouraged 
to explicitly set the type of identity specification that is being used.
A subset of these rules can be used as third arg in the 
.B olcAuthzRegexp
statement (see below); significantly, the 
.IR URI ,
provided it results in exactly one entry,
and the
.I dn.exact:<dn> 
forms.
.RE
.TP
.B olcAuthzRegexp: <match> <replace>
Used by the authentication framework to convert simple user names,
such as provided by SASL subsystem, or extracted from certificates
in case of cert-based SASL EXTERNAL, or provided within the RFC 4370
"proxied authorization" control, to an LDAP DN used for
authorization purposes.  Note that the resulting DN need not refer
to an existing entry to be considered valid.  When an authorization
request is received from the SASL subsystem, the SASL 
.BR USERNAME ,
.BR REALM , 
and
.B MECHANISM
are taken, when available, and combined into a name of the form
.RS
.RS
.TP
.B UID=<username>[[,CN=<realm>],CN=<mechanism>],CN=auth

.RE
This name is then compared against the
.B match
POSIX (''extended'') regular expression, and if the match is successful,
the name is replaced with the
.B replace
string.  If there are wildcard strings in the 
.B match
regular expression that are enclosed in parenthesis, e.g. 
.RS
.TP
.B UID=([^,]*),CN=.*

.RE
then the portion of the name that matched the wildcard will be stored
in the numbered placeholder variable $1. If there are other wildcard strings
in parenthesis, the matching strings will be in $2, $3, etc. up to $9. The 
placeholders can then be used in the 
.B replace
string, e.g. 
.RS
.TP
.B UID=$1,OU=Accounts,DC=example,DC=com 

.RE
The replaced name can be either a DN, i.e. a string prefixed by "dn:",
or an LDAP URI.
If the latter, the server will use the URI to search its own database(s)
and, if the search returns exactly one entry, the name is
replaced by the DN of that entry.   The LDAP URI must have no
hostport, attrs, or extensions components, but the filter is mandatory,
e.g.
.RS
.TP
.B ldap:///OU=Accounts,DC=example,DC=com??one?(UID=$1)

.RE
The protocol portion of the URI must be strictly
.BR ldap .
Note that this search is subject to access controls.  Specifically,
the authentication identity must have "auth" access in the subject.

Multiple 
.B olcAuthzRegexp 
values can be specified to allow for multiple matching 
and replacement patterns. The matching patterns are checked in the order they 
appear in the attribute, stopping at the first successful match.

.\".B Caution:
.\"Because the plus sign + is a character recognized by the regular expression engine,
.\"and it will appear in names that include a REALM, be careful to escape the
.\"plus sign with a backslash \\+ to remove the character's special meaning.
.RE
.TP
.B olcConcurrency: <integer>
Specify a desired level of concurrency.  Provided to the underlying
thread system as a hint.  The default is not to provide any hint. This setting
is only meaningful on some platforms where there is not a one to one
correspondence between user threads and kernel threads.
.TP
.B olcConnMaxPending: <integer>
Specify the maximum number of pending requests for an anonymous session.
If requests are submitted faster than the server can process them, they
will be queued up to this limit. If the limit is exceeded, the session
is closed. The default is 100.
.TP
.B olcConnMaxPendingAuth: <integer>
Specify the maximum number of pending requests for an authenticated session.
The default is 1000.
.TP
.B olcDisallows: <features>
Specify a set of features to disallow (default none).
.B bind_anon
disables acceptance of anonymous bind requests.  Note that this setting
does not prohibit anonymous directory access (See "require authc").
.B bind_simple
disables simple (bind) authentication.
.B tls_2_anon
disables forcing session to anonymous status (see also
.BR tls_authc )
upon StartTLS operation receipt.
.B tls_authc
disallows the StartTLS operation if authenticated (see also
.BR tls_2_anon ).
.B proxy_authz_non_critical
disables acceptance of the proxied authorization control (RFC4370)
with criticality set to FALSE.
.B dontusecopy_non_critical
disables acceptance of the dontUseCopy control (a work in progress)
with criticality set to FALSE.
.TP
.B olcGentleHUP: { TRUE | FALSE }
A SIGHUP signal will only cause a 'gentle' shutdown-attempt:
.B Slapd
will stop listening for new connections, but will not close the
connections to the current clients.  Future write operations return
unwilling-to-perform, though.  Slapd terminates when all clients
have closed their connections (if they ever do), or \- as before \-
if it receives a SIGTERM signal.  This can be useful if you wish to
terminate the server and start a new
.B slapd
server
.B with another database,
without disrupting the currently active clients.
The default is FALSE.  You may wish to use
.B olcIdleTimeout
along with this option.
.TP
.B olcIdleTimeout: <integer>
Specify the number of seconds to wait before forcibly closing
an idle client connection.  A setting of 0 disables this
feature.  The default is 0. You may also want to set the
.B olcWriteTimeout
option.
.TP
.B olcIndexHash64: { TRUE | FALSE }
Use a 64 bit hash for indexing. The default is to use 32 bit hashes.
These hashes are used for equality and substring indexing. The 64 bit
version may be needed to avoid index collisions when the number of
indexed values exceeds ~64 million. (Note that substring indexing
generates multiple index values per actual attribute value.)
Indices generated with 32 bit hashes are incompatible with the 64 bit
version, and vice versa. Any existing databases must be fully reloaded
when changing this setting. This directive is only supported on 64 bit CPUs.
.TP
.B olcIndexIntLen: <integer>
Specify the key length for ordered integer indices. The most significant
bytes of the binary integer will be used for index keys. The default
value is 4, which provides exact indexing for 31 bit values.
A floating point representation is used to index too large values.
.TP
.B olcIndexSubstrIfMaxlen: <integer>
Specify the maximum length for subinitial and subfinal indices. Only
this many characters of an attribute value will be processed by the
indexing functions; any excess characters are ignored. The default is 4.
.TP
.B olcIndexSubstrIfMinlen: <integer>
Specify the minimum length for subinitial and subfinal indices. An
attribute value must have at least this many characters in order to be
processed by the indexing functions. The default is 2.
.TP
.B olcIndexSubstrAnyLen: <integer>
Specify the length used for subany indices. An attribute value must have
at least this many characters in order to be processed. Attribute values
longer than this length will be processed in segments of this length. The
default is 4. The subany index will also be used in subinitial and
subfinal index lookups when the filter string is longer than the
.I olcIndexSubstrIfMaxlen
value.
.TP
.B olcIndexSubstrAnyStep: <integer>
Specify the steps used in subany index lookups. This value sets the offset
for the segments of a filter string that are processed for a subany index
lookup. The default is 2. For example, with the default values, a search
using this filter "cn=*abcdefgh*" would generate index lookups for
"abcd", "cdef", and "efgh".

.LP
Note: Indexing support depends on the particular backend in use. Also,
changing these settings will generally require deleting any indices that
depend on these parameters and recreating them with
.BR slapindex (8).

.TP
.B olcListenerThreads: <integer>
Specify the number of threads to use for the connection manager.
The default is 1 and this is typically adequate for up to 16 CPU cores.
The value should be set to a power of 2.
.TP
.B olcLocalSSF: <SSF>
Specifies the Security Strength Factor (SSF) to be given local LDAP sessions,
such as those to the ldapi:// listener.  For a description of SSF values,
see 
.BR olcSaslSecProps 's
.B minssf
option description.  The default is 71.
.TP
.B olcLogFile: <filename>
Specify a file for recording slapd debug messages. These messages are
unrelated to messages exposed by the
.B olcLogLevel
configuration parameter. This setting only affects the slapd daemon and has
no effect on the command line tools. By default these messages
only go to stderr and are not recorded anywhere else.
Specifying a logfile copies messages to both stderr and the logfile.
.TP
.B olcLogFileFormat: debug | syslog-utc | syslog-localtime
Specify the prefix format for messages written to the logfile. The debug
format is the normal format used for slapd debug messages, with a timestamp
in hexadecimal, followed by a thread ID.  The other options are to
use syslog(3) style prefixes, with timestamps either in UTC or in the
local timezone. The default is debug format.
.TP
.B olcLogFileOnly: TRUE | FALSE
Specify that debug messages should only go to the configured logfile, and
not to stderr.
.TP
.B olcLogFileRotate: <max> <Mbytes> <hours>
Specify automatic rotation for the configured logfile as the maximum
number of old logfiles to retain, a maximum size in megabytes to allow a
logfile to grow before rotation, and a maximum age in hours for a logfile
to be used before rotation. The maximum number must be in the range 1-99.
Setting Mbytes or hours to zero disables the size or age check, respectively.
At least one of Mbytes or hours must be non-zero. By default no automatic
rotation will be performed.
.TP
.B olcLogLevel: <integer> [...]
Specify the level at which debugging statements and operation 
statistics should be syslogged (currently logged to the
.BR syslogd (8) 
LOG_LOCAL4 facility).
They must be considered subsystems rather than increasingly verbose 
log levels.
Some messages with higher priority are logged regardless 
of the configured loglevel as soon as any logging is configured.
Log levels are additive, and available levels are:
.RS
.RS
.PD 0
.TP
.B 1
.B (0x1 trace)
trace function calls
.TP
.B 2
.B (0x2 packets)
debug packet handling
.TP
.B 4
.B (0x4 args)
heavy trace debugging (function args)
.TP
.B 8
.B (0x8 conns)
connection management
.TP
.B 16
.B (0x10 BER)
print out packets sent and received
.TP
.B 32
.B (0x20 filter)
search filter processing
.TP
.B 64
.B (0x40 config)
configuration file processing
.TP
.B 128
.B (0x80 ACL)
access control list processing
.TP
.B 256
.B (0x100 stats)
connections, LDAP operations, results (recommended)
.TP
.B 512
.B (0x200 stats2)
stats2 log entries sent
.TP
.B 1024
.B (0x400 shell)
print communication with shell backends
.TP
.B 2048
.B (0x800 parse)
entry parsing
\".TP
\".B 4096
\".B (0x1000 cache)
\"caching (unused)
\".TP
\".B 8192
\".B (0x2000 index)
\"data indexing (unused)
.TP
.B 16384
.B (0x4000 sync)
LDAPSync replication
.TP
.B 32768
.B (0x8000 none)
only messages that get logged whatever log level is set
.PD
.RE
The desired log level can be input as a single integer that combines 
the (ORed) desired levels, both in decimal or in hexadecimal notation,
as a list of integers (that are ORed internally),
or as a list of the names that are shown between parenthesis, such that
.LP
.nf
    olcLogLevel: 129
    olcLogLevel: 0x81
    olcLogLevel: 128 1
    olcLogLevel: 0x80 0x1
    olcLogLevel: acl trace
.fi
.LP
are equivalent.
The keyword 
.B any
can be used as a shortcut to enable logging at all levels (equivalent to \-1).
The keyword
.BR none ,
or the equivalent integer representation, causes those messages
that are logged regardless of the configured olcLogLevel to be logged.
In fact, if no olcLogLevel (or a 0 level) is defined, no logging occurs, 
so at least the 
.B none
level is required to have high priority messages logged.

Note that the
.BR packets ,
.BR BER ,
and
.B parse
levels are only available as debug output on stderr, and are not
sent to syslog.

This setting defaults to \fBstats\fP.
This level should usually also be included when using other loglevels, to
help analyze the logs.
.RE
.TP
.B olcMaxFilterDepth: <integer>
Specify the maximum depth of nested filters in search requests.
The default is 1000.
.TP
.B olcPasswordCryptSaltFormat: <format>
Specify the format of the salt passed to
.BR crypt (3)
when generating {CRYPT} passwords (see
.BR olcPasswordHash )
during processing of LDAP Password Modify Extended Operations (RFC 3062).

This string needs to be in
.BR sprintf (3)
format and may include one (and only one) %s conversion.
This conversion will be substituted with a string of random
characters from [A\-Za\-z0\-9./].  For example, "%.2s"
provides a two character salt and "$1$%.8s" tells some
versions of crypt(3) to use an MD5 algorithm and provides
8 random characters of salt.  The default is "%s", which
provides 31 characters of salt.
.TP
.B olcPidFile: <filename>
The (absolute) name of a file that will hold the 
.B slapd
server's process ID (see
.BR getpid (2)).
.TP
.B olcPluginLogFile: <filename>
The ( absolute ) name of a file that will contain log
messages from
.B SLAPI
plugins. See
.BR slapd.plugin (5)
for details.
.TP
.B olcReferral: <url>
Specify the referral to pass back when
.BR slapd (8)
cannot find a local database to handle a request.
If multiple values are specified, each url is provided.
.TP
.B olcReverseLookup: TRUE | FALSE
Enable/disable client name unverified reverse lookup (default is 
.BR FALSE 
if compiled with \-\-enable\-rlookups).
.TP
.B olcRootDSE: <file>
Specify the name of an LDIF(5) file containing user defined attributes
for the root DSE.  These attributes are returned in addition to the
attributes normally produced by slapd.

The root DSE is an entry with information about the server and its
capabilities, in operational attributes.
It has the empty DN, and can be read with e.g.:
.ti +4
ldapsearch \-x \-b "" \-s base "+"
.br
See RFC 4512 section 5.1 for details.
.TP
.B olcSaslAuxprops: <plugin> [...]
Specify which auxprop plugins to use for authentication lookups. The
default is empty, which just uses slapd's internal support. Usually
no other auxprop plugins are needed.
.TP
.B olcSaslAuxpropsDontUseCopy: <attr> [...]
Specify which attribute(s) should be subject to the don't use copy control. This
is necessary for some SASL mechanisms such as OTP to work in a replicated
environment. The attribute "cmusaslsecretOTP" is the default value.
.TP
.B olcSaslAuxpropsDontUseCopyIgnore TRUE | FALSE
Used to disable replication of the attribute(s) defined by
olcSaslAuxpropsDontUseCopy and instead use a local value for the attribute. This
allows the SASL mechanism to continue to work if the provider is offline. This can
cause replication inconsistency. Defaults to FALSE.
.TP
.B olcSaslHost: <fqdn>
Used to specify the fully qualified domain name used for SASL processing.
.TP
.B olcSaslRealm: <realm>
Specify SASL realm.  Default is empty.
.TP
.B olcSaslCbinding: none | tls-unique | tls-endpoint
Specify the channel-binding type, see also LDAP_OPT_X_SASL_CBINDING.
Default is none.
.TP
.B olcSaslSecProps: <properties>
Used to specify Cyrus SASL security properties.
The
.B none
flag (without any other properties) causes the flag properties
default, "noanonymous,noplain", to be cleared.
The
.B noplain
flag disables mechanisms susceptible to simple passive attacks.
The
.B noactive
flag disables mechanisms susceptible to active attacks.
The
.B nodict
flag disables mechanisms susceptible to passive dictionary attacks.
The
.B noanonymous
flag disables mechanisms which support anonymous login.
The
.B forwardsec
flag require forward secrecy between sessions.
The
.B passcred
require mechanisms which pass client credentials (and allow
mechanisms which can pass credentials to do so).
The
.B minssf=<factor> 
property specifies the minimum acceptable
.I security strength factor
as an integer approximate to effective key length used for
encryption.  0 (zero) implies no protection, 1 implies integrity
protection only, 128 allows RC4, Blowfish and other similar ciphers,
256 will require modern ciphers.  The default is 0.
The
.B maxssf=<factor> 
property specifies the maximum acceptable
.I security strength factor
as an integer (see minssf description).  The default is INT_MAX.
The
.B maxbufsize=<size> 
property specifies the maximum security layer receive buffer
size allowed.  0 disables security layers.  The default is 65536.
.TP
.B olcServerID: <integer> [<URL>]
Specify an integer ID from 0 to 4095 for this server. The ID may also be
specified as a hexadecimal ID by prefixing the value with "0x".
Non-zero IDs are required when using multi-provider replication and each
provider must have a unique non-zero ID. Note that this requirement also
applies to separate providers contributing to a glued set of databases.
If the URL is provided, this directive may be specified
multiple times, providing a complete list of participating servers
and their IDs. The fully qualified hostname of each server should be
used in the supplied URLs. The IDs are used in the "replica id" field
of all CSNs generated by the specified server. The default value is zero, which
is only valid for single provider replication.
Example:
.LP
.nf
	olcServerID: 1 ldap://ldap1.example.com
	olcServerID: 2 ldap://ldap2.example.com
.fi
.TP
.B olcSockbufMaxIncoming: <integer>
Specify the maximum incoming LDAP PDU size for anonymous sessions.
The default is 262143.
.TP
.B olcSockbufMaxIncomingAuth: <integer>
Specify the maximum incoming LDAP PDU size for authenticated sessions.
The default is 4194303.
.TP
.B olcTCPBuffer [listener=<URL>] [{read|write}=]<size>
Specify the size of the TCP buffer.
A global value for both read and write TCP buffers related to any listener
is defined, unless the listener is explicitly specified,
or either the read or write qualifiers are used.
See
.BR tcp (7)
for details.
Note that some OS-es implement automatic TCP buffer tuning.
.TP
.B olcThreads: <integer>
Specify the maximum size of the primary thread pool.
The default is 16; the minimum value is 2.
.TP
.B olcThreadQueues: <integer>
Specify the number of work queues to use for the primary thread pool.
The default is 1 and this is typically adequate for up to 8 CPU cores.
The value should not exceed the number of CPUs in the system.
.TP
.B olcToolThreads: <integer>
Specify the maximum number of threads to use in tool mode.
This should not be greater than the number of CPUs in the system.
The default is 1.
.TP
.B olcWriteTimeout: <integer>
Specify the number of seconds to wait before forcibly closing
a connection with an outstanding write.  This allows recovery from
various network hang conditions.  A setting of 0 disables this
feature.  The default is 0.
.SH TLS OPTIONS
If
.B slapd
is built with support for Transport Layer Security, there are more options
you can specify.
.TP
.B olcTLSCipherSuite: <cipher-suite-spec>
Permits configuring what ciphers will be accepted and the preference order.
<cipher-suite-spec> should be a cipher specification for the TLS library
in use (OpenSSL or GnuTLS).
This directive is not supported when using MbedTLS.
Example:
.RS
.RS
.TP
.I OpenSSL:
olcTLSCipherSuite: HIGH:MEDIUM:+SSLv2
.TP
.I GnuTLS:
olcTLSCiphersuite: SECURE256:!AES-128-CBC
.RE

To check what ciphers a given spec selects in OpenSSL, use:

.nf
	openssl ciphers \-v <cipher-suite-spec>
.fi

With GnuTLS the available specs can be found in the manual page of
.BR gnutls\-cli (1)
(see the description of the
option
.BR \-\-priority ).

In older versions of GnuTLS, where gnutls\-cli does not support the option
\-\-priority, you can obtain the \(em more limited \(em list of ciphers by calling:

.nf
	gnutls\-cli \-l
.fi
.RE
.TP
.B olcTLSCACertificateFile: <filename>
Specifies the file that contains certificates for all of the Certificate
Authorities that
.B slapd
will recognize.  The certificate for
the CA that signed the server certificate must be included among
these certificates. If the signing CA was not a top-level (root) CA,
certificates for the entire sequence of CA's from the signing CA to
the top-level CA should be present. Multiple certificates are simply
appended to the file; the order is not significant.
.TP
.B olcTLSCACertificatePath: <path>
Specifies the path of directories that contain Certificate Authority
certificates in separate individual files. Usually only one of this
or the olcTLSCACertificateFile is defined. If both are specified, both
locations will be used. Multiple directories may be specified,
separated by a semi-colon.
.TP
.B olcTLSCertificateFile: <filename>
Specifies the file that contains the
.B slapd
server certificate.

When using OpenSSL that file may also contain any number of intermediate
certificates after the server certificate.
.TP
.B olcTLSCertificateKeyFile: <filename>
Specifies the file that contains the
.B slapd
server private key that matches the certificate stored in the
.B olcTLSCertificateFile
file. If the private key is protected with a password, the password must
be manually typed in when slapd starts.  Usually the private key is not
protected with a password, to allow slapd to start without manual
intervention, so
it is of critical importance that the file is protected carefully. 
.TP
.B olcTLSDHParamFile: <filename>
This directive specifies the file that contains parameters for Diffie-Hellman
ephemeral key exchange.  This is required in order to use a DSA certificate on
the server, or an RSA certificate missing the "key encipherment" key usage.
Note that setting this option may also enable
Anonymous Diffie-Hellman key exchanges in certain non-default cipher suites.
Anonymous key exchanges should generally be avoided since they provide no
actual client or server authentication and provide no protection against
man-in-the-middle attacks.
You should append "!ADH" to your cipher suites to ensure that these suites
are not used.
This directive is not supported when using MbedTLS.
.TP
.B olcTLSECName: <name>
Specify the name of the curve(s) to use for Elliptic curve Diffie-Hellman
ephemeral key exchange.  This option is only used for OpenSSL.
This option is not used with GnuTLS; the curves may be
chosen in the GnuTLS ciphersuite specification.
.TP
.B olcTLSProtocolMin: <major>[.<minor>]
Specifies minimum SSL/TLS protocol version that will be negotiated.
If the server doesn't support at least that version,
the SSL handshake will fail.
To require TLS 1.x or higher, set this option to 3.(x+1),
e.g.,

.nf
	olcTLSProtocolMin: 3.2
.fi

would require TLS 1.1.
Specifying a minimum that is higher than that supported by the
OpenLDAP implementation will result in it requiring the
highest level that it does support.
This directive is ignored with GnuTLS.
.TP
.B olcTLSRandFile: <filename>
Specifies the file to obtain random bits from when /dev/[u]random
is not available.  Generally set to the name of the EGD/PRNGD socket.
The environment variable RANDFILE can also be used to specify the filename.
This directive is ignored with GnuTLS.
.TP
.B olcTLSVerifyClient: <level>
Specifies what checks to perform on client certificates in an
incoming TLS session, if any.
The
.B <level>
can be specified as one of the following keywords:
.RS
.TP
.B never
This is the default.
.B slapd
will not ask the client for a certificate.
.TP
.B allow
The client certificate is requested.  If no certificate is provided,
the session proceeds normally.  If a bad certificate is provided,
it will be ignored and the session proceeds normally.
.TP
.B try
The client certificate is requested.  If no certificate is provided,
the session proceeds normally.  If a bad certificate is provided,
the session is immediately terminated.
.TP
.B demand | hard | true
These keywords are all equivalent, for compatibility reasons.
The client certificate is requested.  If no certificate is provided,
or a bad certificate is provided, the session is immediately terminated.

Note that a valid client certificate is required in order to use the
SASL EXTERNAL authentication mechanism with a TLS session.  As such,
a non-default
.B olcTLSVerifyClient
setting must be chosen to enable SASL EXTERNAL authentication.
.RE
.TP
.B olcTLSCRLCheck: <level>
Specifies if the Certificate Revocation List (CRL) of the CA should be 
used to verify if the client certificates have not been revoked. This
requires
.B olcTLSCACertificatePath
parameter to be set. This parameter is ignored with GnuTLS.
.B <level>
can be specified as one of the following keywords:
.RS
.TP
.B none
No CRL checks are performed
.TP
.B peer
Check the CRL of the peer certificate
.TP
.B all
Check the CRL for a whole certificate chain
.RE
.TP
.B olcTLSCRLFile: <filename>
Specifies a file containing a Certificate Revocation List to be used
for verifying that certificates have not been revoked. This parameter is
only valid when using GnuTLS.
.SH DYNAMIC MODULE OPTIONS
If
.B slapd
is compiled with \-\-enable\-modules then the module-related entries will
be available. These entries are named
.B cn=module{x},cn=config
and
must have the olcModuleList objectClass. One entry should be created
per
.B olcModulePath.
Normally the config engine generates the "{x}" index in the RDN
automatically, so it can be omitted when initially loading these entries.
.TP
.B olcModuleLoad: <filename> [<arguments>...]
Specify the name of a dynamically loadable module to load and any
additional arguments if supported by the module. The filename
may be an absolute path name or a simple filename. Non-absolute names
are searched for in the directories specified by the
.B olcModulePath
option.
.TP
.B olcModulePath: <pathspec>
Specify a list of directories to search for loadable modules. Typically
the path is colon-separated but this depends on the operating system.
The default is MODULEDIR, which is where the standard OpenLDAP install
will place its modules. 
.SH SCHEMA OPTIONS
Schema definitions are created as entries in the
.B cn=schema,cn=config
subtree. These entries must have the olcSchemaConfig objectClass.
As noted above, the actual
.B cn=schema,cn=config
entry is predefined and any values specified for it are ignored.

.HP
.hy 0
.B olcAttributetypes: "(\ <oid>\
 [NAME\ <name>]\
 [DESC\ <description>]\
 [OBSOLETE]\
 [SUP\ <oid>]\
 [EQUALITY\ <oid>]\
 [ORDERING\ <oid>]\
 [SUBSTR\ <oid>]\
 [SYNTAX\ <oidlen>]\
 [SINGLE\-VALUE]\
 [COLLECTIVE]\
 [NO\-USER\-MODIFICATION]\
 [USAGE\ <attributeUsage>]\ )"
.RS
Specify an attribute type using the LDAPv3 syntax defined in RFC 4512.
The slapd parser extends the RFC 4512 definition by allowing string
forms as well as numeric OIDs to be used for the attribute OID and
attribute syntax OID.
(See the
.B olcObjectIdentifier
description.) 
.RE

.HP
.hy 0
.B olcDitContentRules: "(\ <oid>\
 [NAME\ <name>]\
 [DESC\ <description>]\
 [OBSOLETE]\
 [AUX\ <oids>]\
 [MUST\ <oids>]\
 [MAY\ <oids>]\
 [NOT\ <oids>]\ )"
.RS
Specify an DIT Content Rule using the LDAPv3 syntax defined in RFC 4512.
The slapd parser extends the RFC 4512 definition by allowing string
forms as well as numeric OIDs to be used for the attribute OID and
attribute syntax OID.
(See the
.B olcObjectIdentifier
description.) 
.RE

.HP
.hy 0
.B olcLdapSyntaxes "(\ <oid>\
 [DESC\ <description>]\
 [X\-SUBST <substitute-syntax>]\ )"
.RS
Specify an LDAP syntax using the LDAPv3 syntax defined in RFC 4512.
The slapd parser extends the RFC 4512 definition by allowing string
forms as well as numeric OIDs to be used for the syntax OID.
(See the
.B objectidentifier
description.)
The slapd parser also honors the
.B X\-SUBST
extension (an OpenLDAP-specific extension), which allows one to use the
.B olcLdapSyntaxes
attribute to define a non-implemented syntax along with another syntax,
the extension value
.IR substitute-syntax ,
as its temporary replacement.
The
.I substitute-syntax
must be defined.
This allows one to define attribute types that make use of non-implemented syntaxes
using the correct syntax OID.
Unless
.B X\-SUBST
is used, this configuration statement would result in an error,
since no handlers would be associated to the resulting syntax structure.
.RE

.HP
.hy 0
.B olcObjectClasses: "(\ <oid>\
 [NAME\ <name>]\
 [DESC\ <description>]\
 [OBSOLETE]\
 [SUP\ <oids>]\
 [{ ABSTRACT | STRUCTURAL | AUXILIARY }]\
 [MUST\ <oids>] [MAY\ <oids>] )"
.RS
Specify an objectclass using the LDAPv3 syntax defined in RFC 4512.
The slapd parser extends the RFC 4512 definition by allowing string
forms as well as numeric OIDs to be used for the object class OID.
(See the
.B
olcObjectIdentifier
description.)  Object classes are "STRUCTURAL" by default.
.RE
.TP
.B olcObjectIdentifier: <name> "{ <oid> | <name>[:<suffix>] }"
Define a string name that equates to the given OID. The string can be used
in place of the numeric OID in objectclass and attribute definitions. The
name can also be used with a suffix of the form ":xx" in which case the
value "oid.xx" will be used.

.SH GENERAL BACKEND OPTIONS
Options in these entries only apply to the configuration of a single
type of backend. All backends may support this class of options, but
currently only back-mdb does.
The entry must be named
.B olcBackend=<databasetype>,cn=config
and must have the olcBackendConfig objectClass.
<databasetype>
should be one of
.BR asyncmeta ,
.BR config ,
.BR dnssrv ,
.BR ldap ,
.BR ldif ,
.BR mdb ,
.BR meta ,
.BR monitor ,
.BR null ,
.BR passwd ,
.BR perl ,
.BR relay ,
.BR sock ,
.BR sql ,
or
.BR wt .
At present, only back-mdb implements any options of this type, so this
entry should not be used for any other backends.

.SH DATABASE OPTIONS
Database options are set in entries named
.B olcDatabase={x}<databasetype>,cn=config
and must have the olcDatabaseConfig objectClass. Normally the config
engine generates the "{x}" index in the RDN automatically, so it
can be omitted when initially loading these entries.

The special frontend database is always numbered "{\-1}" and the config
database is always numbered "{0}".

.SH GLOBAL DATABASE OPTIONS
Options in this section may be set in the special "frontend" database
and inherited in all the other databases. These options may be altered
by further settings in each specific database. The frontend entry must
be named
.B olcDatabase=frontend,cn=config
and must have the olcFrontendConfig objectClass.
.TP
.B olcAccess: to <what> "[ by <who> <access> <control> ]+"
Grant access (specified by <access>) to a set of entries and/or
attributes (specified by <what>) by one or more requestors (specified
by <who>).
If no access controls are present, the default policy
allows anyone and everyone to read anything but restricts
updates to rootdn.  (e.g., "olcAccess: to * by * read").
See
.BR slapd.access (5)
and the "OpenLDAP Administrator's Guide" for details.

Access controls set in the frontend are appended to any access
controls set on the specific databases.
The rootdn of a database can always read and write EVERYTHING
in that database.

Extra special care must be taken with the access controls on the
config database. Unlike other databases, the default policy for the
config database is to only allow access to the rootdn. Regular users
should not have read access, and write access should be granted very
carefully to privileged administrators.

.TP
.B olcDefaultSearchBase: <dn>
Specify a default search base to use when client submits a
non-base search request with an empty base DN.
Base scoped search requests with an empty base DN are not affected.
This setting is only allowed in the frontend entry.
.TP
.B olcExtraAttrs: <attr>
Lists what attributes need to be added to search requests.
Local storage backends return the entire entry to the frontend.
The frontend takes care of only returning the requested attributes
that are allowed by ACLs.
However, features like access checking and so may need specific
attributes that are not automatically returned by remote storage
backends, like proxy backends and so on.
.B <attr>
is an attribute that is needed for internal purposes
and thus always needs to be collected, even when not explicitly
requested by clients.
This attribute is multi-valued.
.TP
.B olcPasswordHash: <hash> [<hash>...]
This option configures one or more hashes to be used in generation of user
passwords stored in the userPassword attribute during processing of
LDAP Password Modify Extended Operations (RFC 3062).
The <hash> must be one of
.BR {SSHA} ,
.BR {SHA} ,
.BR {SMD5} ,
.BR {MD5} ,
.BR {CRYPT} ,
and
.BR {CLEARTEXT} .
The default is
.BR {SSHA} .

.B {SHA}
and
.B {SSHA}
use the SHA-1 algorithm (FIPS 160-1), the latter with a seed.

.B {MD5}
and
.B {SMD5}
use the MD5 algorithm (RFC 1321), the latter with a seed.

.B {CRYPT}
uses the
.BR crypt (3).

.B {CLEARTEXT}
indicates that the new password should be
added to userPassword as clear text.

Note that this option does not alter the normal user applications
handling of userPassword during LDAP Add, Modify, or other LDAP operations.
This setting is only allowed in the frontend entry.
.TP
.B olcReadOnly: TRUE | FALSE
This option puts the database into "read-only" mode.  Any attempts to 
modify the database will return an "unwilling to perform" error.  By
default, olcReadOnly is FALSE. Note that when this option is set
TRUE on the frontend, it cannot be reset without restarting the
server, since further writes to the config database will be rejected.
.TP
.B olcRequires: <conditions>
Specify a set of conditions to require (default none).
The directive may be specified globally and/or per-database;
databases inherit global conditions, so per-database specifications
are additive.
.B bind
requires bind operation prior to directory operations.
.B LDAPv3
requires session to be using LDAP version 3.
.B authc
requires authentication prior to directory operations.
.B SASL
requires SASL authentication prior to directory operations.
.B strong
requires strong authentication prior to directory operations.
The strong keyword allows protected "simple" authentication
as well as SASL authentication.
.B none
may be used to require no conditions (useful to clear out globally
set conditions within a particular database); it must occur first
in the list of conditions.
.TP
.B olcRestrict: <oplist>
Specify a list of operations that are restricted.
Restrictions on a specific database override any frontend setting.
Operations can be any of 
.BR add ,
.BR bind ,
.BR compare ,
.BR delete ,
.BR extended[=<OID>] ,
.BR modify ,
.BR rename ,
.BR search ,
or the special pseudo-operations
.B read
and
.BR write ,
which respectively summarize read and write operations.
The use of 
.I restrict write
is equivalent to 
.I olcReadOnly: TRUE
(see above).
The 
.B extended
keyword allows one to indicate the OID of the specific operation
to be restricted.
.TP
.B olcSchemaDN: <dn>
Specify the distinguished name for the subschema subentry that
controls the entries on this server.  The default is "cn=Subschema".
.TP
.B olcSecurity: <factors>
Specify a set of security strength factors (separated by white space)
to require (see
.BR olcSaslSecprops 's
.B minssf
option for a description of security strength factors).
The directive may be specified globally and/or per-database.
.B ssf=<n>
specifies the overall security strength factor.
.B transport=<n>
specifies the transport security strength factor.
.B tls=<n>
specifies the TLS security strength factor.
.B sasl=<n>
specifies the SASL security strength factor.
.B update_ssf=<n>
specifies the overall security strength factor to require for
directory updates.
.B update_transport=<n>
specifies the transport security strength factor to require for
directory updates.
.B update_tls=<n>
specifies the TLS security strength factor to require for
directory updates.
.B update_sasl=<n>
specifies the SASL security strength factor to require for
directory updates.
.B simple_bind=<n>
specifies the security strength factor required for
.I simple
username/password authentication.
Note that the
.B transport
factor is measure of security provided by the underlying transport,
e.g. ldapi:// (and eventually IPSEC).  It is not normally used.
.TP
.B olcSizeLimit: {<integer>|unlimited}
.TP
.B olcSizeLimit: size[.{soft|hard}]=<integer> [...]
Specify the maximum number of entries to return from a search operation.
The default size limit is 500.
Use
.B unlimited
to specify no limits.
The second format allows a fine grain setting of the size limits.
If no special qualifiers are specified, both soft and hard limits are set.
Extra args can be added in the same value.
Additional qualifiers are available; see
.BR olcLimits
for an explanation of all of the different flags.
.TP
.B olcSortVals: <attr> [...]
Specify a list of multi-valued attributes whose values will always
be maintained in sorted order. Using this option will allow Modify,
Compare, and filter evaluations on these attributes to be performed
more efficiently. The resulting sort order depends on the
attributes' syntax and matching rules and may not correspond to
lexical order or any other recognizable order.
This setting is only allowed in the frontend entry.
.TP
.B olcTimeLimit: {<integer>|unlimited}
.TP
.B olcTimeLimit: time[.{soft|hard}]=<integer> [...]
Specify the maximum number of seconds (in real time)
.B slapd
will spend answering a search request.  The default time limit is 3600.
Use
.B unlimited
to specify no limits.
The second format allows a fine grain setting of the time limits.
Extra args can be added in the same value. See
.BR olcLimits
for an explanation of the different flags.

.SH GENERAL DATABASE OPTIONS
Options in this section only apply to the specific database for
which they are defined.  They are supported by every
type of backend. All of the Global Database Options may also be
used here.
.TP
.B olcAddContentAcl: TRUE | FALSE
Controls whether Add operations will perform ACL checks on
the content of the entry being added. This check is off
by default. See the
.BR slapd.access (5)
manual page for more details on ACL requirements for
Add operations.
.TP
.B olcHidden: TRUE | FALSE
Controls whether the database will be used to answer
queries. A database that is hidden will never be
selected to answer any queries, and any suffix configured
on the database will be ignored in checks for conflicts
with other databases. By default, olcHidden is FALSE.
.TP
.B olcLastMod: TRUE | FALSE
Controls whether
.B slapd
will automatically maintain the 
modifiersName, modifyTimestamp, creatorsName, and 
createTimestamp attributes for entries. It also controls
the entryCSN and entryUUID attributes, which are needed
by the syncrepl provider. By default, olcLastMod is TRUE.
.TP
.B olcLastBind: TRUE | FALSE
Controls whether
.B slapd
will automatically maintain the pwdLastSuccess attribute for
entries. By default, olcLastBind is FALSE.
.TP
.B olcLastBindPrecision: <integer>
If olcLastBind is enabled, specifies how frequently pwdLastSuccess
will be updated. More than
.B integer
seconds must have passed since the last successful bind. In a
replicated environment with frequent bind activity it may be
useful to set this to a large value. On a backend, if set to
.B 0
(the default), the value set on the frontend is used.
.TP
.B olcLimits: <selector> <limit> [<limit> [...]]
Specify time and size limits based on the operation's initiator or
base DN.
The argument
.B <selector>
can be any of
.RS
.RS
.TP
anonymous | users | [<dnspec>=]<pattern> | group[/oc[/at]]=<pattern>

.RE
with
.RS
.TP
<dnspec> ::= dn[.<type>][.<style>]
.TP
<type>  ::= self | this
.TP
<style> ::= exact | base | onelevel | subtree | children | regex | anonymous

.RE
DN type
.B self
is the default and means the bound user, while
.B this
means the base DN of the operation.
The term
.B anonymous
matches all unauthenticated clients.
The term
.B users
matches all authenticated clients;
otherwise an
.B exact
dn pattern is assumed unless otherwise specified by qualifying 
the (optional) key string
.B dn
with 
.B exact
or
.B base
(which are synonyms), to require an exact match; with
.BR onelevel , 
to require exactly one level of depth match; with
.BR subtree ,
to allow any level of depth match, including the exact match; with
.BR children ,
to allow any level of depth match, not including the exact match;
.BR regex
explicitly requires the (default) match based on POSIX (''extended'')
regular expression pattern.
Finally,
.B anonymous
matches unbound operations; the 
.B pattern
field is ignored.
The same behavior is obtained by using the 
.B anonymous
form of the
.B <selector>
clause.
The term
.BR group ,
with the optional objectClass
.B oc
and attributeType
.B at
fields, followed by
.BR pattern ,
sets the limits for any DN listed in the values of the
.B at
attribute (default
.BR member )
of the 
.B oc
group objectClass (default
.BR groupOfNames )
whose DN exactly matches
.BR pattern .

The currently supported limits are 
.B size
and 
.BR time .

The syntax for time limits is 
.BR time[.{soft|hard}]=<integer> ,
where 
.I integer
is the number of seconds slapd will spend answering a search request.
If no time limit is explicitly requested by the client, the 
.BR soft
limit is used; if the requested time limit exceeds the
.BR hard
.\"limit, an
.\".I "Administrative limit exceeded"
.\"error is returned.
limit, the value of the limit is used instead.
If the
.BR hard
limit is set to the keyword 
.IR soft ,
the soft limit is used in either case; if it is set to the keyword 
.IR unlimited , 
no hard limit is enforced.
Explicit requests for time limits smaller or equal to the
.BR hard 
limit are honored.
If no limit specifier is set, the value is assigned to the 
.BR soft 
limit, and the
.BR hard
limit is set to
.IR soft ,
to preserve the original behavior.

The syntax for size limits is
.BR size[.{soft|hard|unchecked}]=<integer> ,
where
.I integer
is the maximum number of entries slapd will return answering a search 
request.
If no size limit is explicitly requested by the client, the
.BR soft
limit is used; if the requested size limit exceeds the
.BR hard
.\"limit, an 
.\".I "Administrative limit exceeded"
.\"error is returned.
limit, the value of the limit is used instead.
If the 
.BR hard
limit is set to the keyword 
.IR soft , 
the soft limit is used in either case; if it is set to the keyword
.IR unlimited , 
no hard limit is enforced.
Explicit requests for size limits smaller or equal to the
.BR hard
limit are honored.
The
.BR unchecked
specifier sets a limit on the number of candidates a search request is allowed
to examine.
The rationale behind it is that searches for non-properly indexed
attributes may result in large sets of candidates, which must be 
examined by
.BR slapd (8)
to determine whether they match the search filter or not.
The
.B unchecked
limit provides a means to drop such operations before they are even 
started.
If the selected candidates exceed the 
.BR unchecked
limit, the search will abort with 
.IR "Unwilling to perform" .
If it is set to the keyword 
.IR unlimited , 
no limit is applied (the default).
If it is set to
.IR disabled ,
the search is not even performed; this can be used to disallow searches
for a specific set of users.
If no limit specifier is set, the value is assigned to the
.BR soft 
limit, and the
.BR hard
limit is set to
.IR soft ,
to preserve the original behavior.

In case of no match, the global limits are used.
The default values are the same as for
.B olcSizeLimit
and
.BR olcTimeLimit ;
no limit is set on 
.BR unchecked .

If 
.B pagedResults
control is requested, the 
.B hard
size limit is used by default, because the request of a specific page size
is considered an explicit request for a limitation on the number
of entries to be returned.
However, the size limit applies to the total count of entries returned within
the search, and not to a single page.
Additional size limits may be enforced; the syntax is
.BR size.pr={<integer>|noEstimate|unlimited} ,
where
.I integer
is the max page size if no explicit limit is set; the keyword
.I noEstimate
inhibits the server from returning an estimate of the total number
of entries that might be returned
(note: the current implementation does not return any estimate).
The keyword
.I unlimited
indicates that no limit is applied to the pagedResults control page size.
The syntax
.B size.prtotal={<integer>|hard|unlimited|disabled}
allows one to set a limit on the total number of entries that the pagedResults
control will return.
By default it is set to the 
.B hard
limit which will use the size.hard value.
When set, 
.I integer
is the max number of entries that the whole search with pagedResults control
can return.
Use 
.I unlimited
to allow unlimited number of entries to be returned, e.g. to allow
the use of the pagedResults control as a means to circumvent size 
limitations on regular searches; the keyword
.I disabled
disables the control, i.e. no paged results can be returned.
Note that the total number of entries returned when the pagedResults control 
is requested cannot exceed the 
.B hard 
size limit of regular searches unless extended by the
.B prtotal
switch.

The \fBolcLimits\fP statement is typically used to let an unlimited
number of entries be returned by searches performed
with the identity used by the consumer for synchronization purposes
by means of the RFC 4533 LDAP Content Synchronization protocol
(see \fBolcSyncrepl\fP for details).

When using subordinate databases, it is necessary for any limits that
are to be applied across the parent and its subordinates to be defined in
both the parent and its subordinates. Otherwise the settings on the
subordinate databases are not honored.
.RE
.TP
.B olcMaxDerefDepth: <depth>
Specifies the maximum number of aliases to dereference when trying to
resolve an entry, used to avoid infinite alias loops. The default is 15.
.TP
.B olcMultiProvider: TRUE | FALSE
This option puts a consumer database into Multi-Provider mode.  Update
operations will be accepted from any user, not just the updatedn.  The
database must already be configured as a syncrepl consumer
before this keyword may be set. This mode also requires a
.B olcServerID
(see above) to be configured.
By default, this setting is FALSE.
.TP
.B olcMonitoring: TRUE | FALSE
This option enables database-specific monitoring in the entry related
to the current database in the "cn=Databases,cn=Monitor" subtree
of the monitor database, if the monitor database is enabled.
Currently, only the MDB database provides database-specific monitoring.
If monitoring is supported by the backend it defaults to TRUE, otherwise
FALSE.
.TP
.B olcPlugin: <plugin_type> <lib_path> <init_function> [<arguments>]
Configure a SLAPI plugin. See the
.BR slapd.plugin (5)
manpage for more details.
.TP
.B olcRootDN: <dn>
Specify the distinguished name that is not subject to access control 
or administrative limit restrictions for operations on this database.
This DN may or may not be associated with an entry.  An empty root
DN (the default) specifies no root access is to be granted.  It is
recommended that the rootdn only be specified when needed (such as
when initially populating a database).  If the rootdn is within
a namingContext (suffix) of the database, a simple bind password
may also be provided using the
.B olcRootPW
directive. Many optional features, including syncrepl, require the
rootdn to be defined for the database.
The
.B olcRootDN
of the
.B cn=config
database defaults to
.B cn=config
itself.
.TP
.B olcRootPW: <password>
Specify a password (or hash of the password) for the rootdn.  The
password can only be set if the rootdn is within the namingContext
(suffix) of the database.
This option accepts all RFC 2307 userPassword formats known to
the server (see 
.B olcPasswordHash
description) as well as cleartext.
.BR slappasswd (8) 
may be used to generate a hash of a password.  Cleartext
and \fB{CRYPT}\fP passwords are not recommended.  If empty
(the default), authentication of the root DN is by other means
(e.g. SASL).  Use of SASL is encouraged.
.TP
.B olcSubordinate: [TRUE | FALSE | advertise]
Specify that the current backend database is a subordinate of another
backend database. A subordinate  database may have only one suffix. This
option may be used to glue multiple databases into a single namingContext.
If the suffix of the current database is within the namingContext of a
superior database, searches against the superior database will be
propagated to the subordinate as well. All of the databases
associated with a single namingContext should have identical rootdns.
Behavior of other LDAP operations is unaffected by this setting. In
particular, it is not possible to use moddn to move an entry from
one subordinate to another subordinate within the namingContext.

If the optional \fBadvertise\fP flag is supplied, the naming context of
this database is advertised in the root DSE. The default is to hide this
database context, so that only the superior context is visible.

If the slap tools
.BR slapcat (8),
.BR slapadd (8),
.BR slapmodify (8),
or
.BR slapindex (8)
are used on the superior database, any glued subordinates that support
these tools are opened as well.

Databases that are glued together should usually be configured with the
same indices (assuming they support indexing), even for attributes that
only exist in some of these databases. In general, all of the glued
databases should be configured as similarly as possible, since the intent
is to provide the appearance of a single directory.

Note that the subordinate functionality is implemented internally
by the \fIglue\fP overlay and as such its behavior will interact with other
overlays in use. By default, the glue overlay is automatically configured as
the last overlay on the superior database. Its position on the database
can be explicitly configured by setting an \fBoverlay glue\fP directive
at the desired position. This explicit configuration is necessary e.g.
when using the \fIsyncprov\fP overlay, which needs to follow \fIglue\fP
in order to work over all of the glued databases. E.g.
.RS
.nf
	dn: olcDatabase={1}mdb,cn=config
	olcSuffix: dc=example,dc=com
	...

	dn: olcOverlay={0}glue,olcDatabase={1}mdb,cn=config
	...

	dn: olcOverlay={1}syncprov,olcDatabase={1}mdb,cn=config
	...
.fi
.RE
See the Overlays section below for more details.
.TP
.B olcSuffix: <dn suffix>
Specify the DN suffix of queries that will be passed to this 
backend database.  Multiple suffix lines can be given and at least one is 
required for each database definition.

If the suffix of one database is "inside" that of another, the database
with the inner suffix must come first in the configuration file.
You may also want to glue such databases together with the
.B olcSubordinate
attribute.
.TP
.B olcSyncUseSubentry: TRUE | FALSE
Store the syncrepl contextCSN in a subentry instead of the context entry
of the database. The subentry's RDN will be "cn=ldapsync". The default is
FALSE, meaning the contextCSN is stored in the context entry.
.HP
.hy 0
.B olcSyncrepl: rid=<replica ID>
.B provider=ldap[s]://<hostname>[:port]
.B searchbase=<base DN>
.B [type=refreshOnly|refreshAndPersist]
.B [interval=dd:hh:mm:ss]
.B [retry=[<retry interval> <# of retries>]+]
.B [filter=<filter str>]
.B [scope=sub|one|base|subord]
.B [attrs=<attr list>]
.B [exattrs=<attr list>]
.B [attrsonly]
.B [sizelimit=<limit>]
.B [timelimit=<limit>]
.B [schemachecking=on|off]
.B [network\-timeout=<seconds>]
.B [timeout=<seconds>]
.B [tcp\-user\-timeout=<milliseconds>]
.B [bindmethod=simple|sasl]
.B [binddn=<dn>]
.B [saslmech=<mech>]
.B [authcid=<identity>]
.B [authzid=<identity>]
.B [credentials=<passwd>]
.B [realm=<realm>]
.B [secprops=<properties>]
.B [keepalive=<idle>:<probes>:<interval>]
.B [starttls=yes|critical]
.B [tls_cert=<file>]
.B [tls_key=<file>]
.B [tls_cacert=<file>]
.B [tls_cacertdir=<path>]
.B [tls_reqcert=never|allow|try|demand]
.B [tls_reqsan=never|allow|try|demand]
.B [tls_cipher_suite=<ciphers>]
.B [tls_ecname=<names>]
.B [tls_crlcheck=none|peer|all]
.B [tls_protocol_min=<major>[.<minor>]]
.B [suffixmassage=<real DN>]
.B [logbase=<base DN>]
.B [logfilter=<filter str>]
.B [syncdata=default|accesslog|changelog]
.B [lazycommit]
.RS
Specify the current database as a consumer which is kept up-to-date with the 
provider content by establishing the current
.BR slapd (8)
as a replication consumer site running a
.B syncrepl
replication engine.
The consumer content is kept synchronized to the provider content using
the LDAP Content Synchronization protocol. Refer to the
"OpenLDAP Administrator's Guide" for detailed information on
setting up a replicated
.B slapd
directory service using the 
.B syncrepl
replication engine.

.B rid
identifies the current
.B syncrepl
directive within the replication consumer site.
It is a non-negative integer not greater than 999 (limited
to three decimal digits).

.B provider
specifies the replication provider site containing the provider content
as an LDAP URI. If <port> is not given, the standard LDAP port number
(389 or 636) is used.

The content of the
.B syncrepl
consumer is defined using a search
specification as its result set. The consumer
.B slapd
will send search requests to the provider
.B slapd
according to the search specification. The search specification includes
.BR searchbase ", " scope ", " filter ", " attrs ", " attrsonly ", " sizelimit ", "
and
.B timelimit
parameters as in the normal search specification. The
.B exattrs
option may also be used to specify attributes that should be omitted
from incoming entries.
The \fBscope\fP defaults to \fBsub\fP, the \fBfilter\fP defaults to
\fB(objectclass=*)\fP, and there is no default \fBsearchbase\fP. The
\fBattrs\fP list defaults to \fB"*,+"\fP to return all user and operational
attributes, and \fBattrsonly\fP and \fBexattrs\fP are unset by default.
The \fBsizelimit\fP and \fBtimelimit\fP only
accept "unlimited" and positive integers, and both default to "unlimited".
The \fBsizelimit\fP and \fBtimelimit\fP parameters define
a consumer requested limitation on the number of entries that can be returned
by the LDAP Content Synchronization operation; these should be left unchanged
from the default otherwise replication may never succeed.
Note, however, that any provider-side limits for the replication identity
will be enforced by the provider regardless of the limits requested
by the LDAP Content Synchronization operation, much like for any other
search operation.

The LDAP Content Synchronization protocol has two operation types.
In the
.B refreshOnly
operation, the next synchronization search operation
is periodically rescheduled at an interval time (specified by 
.B interval
parameter; 1 day by default)
after each synchronization operation finishes.
In the
.B refreshAndPersist
operation, a synchronization search remains persistent in the provider slapd.
Further updates to the provider will generate
.B searchResultEntry
to the consumer slapd as the search responses to the persistent
synchronization search. If the initial search fails due to an error, the
next synchronization search operation is periodically rescheduled at an
interval time (specified by
.B interval
parameter; 1 day by default)

If an error occurs during replication, the consumer will attempt to
reconnect according to the
.B retry
parameter which is a list of the <retry interval> and <# of retries> pairs.
For example, retry="60 10 300 3" lets the consumer retry every 60 seconds
for the first 10 times and then retry every 300 seconds for the next 3
times before stop retrying. The `+' in <# of retries> means indefinite
number of retries until success.
If no
.B retry
is specified, by default syncrepl retries every hour forever.

The schema checking can be enforced at the LDAP Sync
consumer site by turning on the
.B schemachecking
parameter. The default is \fBoff\fP.
Schema checking \fBon\fP means that replicated entries must have
a structural objectClass, must obey to objectClass requirements
in terms of required/allowed attributes, and that naming attributes
and distinguished values must be present.
As a consequence, schema checking should be \fBoff\fP when partial
replication is used.

The
.B network\-timeout
parameter sets how long the consumer will wait to establish a
network connection to the provider. Once a connection is
established, the
.B timeout
parameter determines how long the consumer will wait for the initial
Bind request to complete. The defaults for these parameters come
from 
.BR ldap.conf (5).
The
.B tcp\-user\-timeout
parameter, if non-zero, corresponds to the
.B TCP_USER_TIMEOUT
set on the target connections, overriding the operating system setting.
Only some systems support the customization of this parameter, it is
ignored otherwise and system-wide settings are used.

A
.B bindmethod
of 
.B simple
requires the options 
.B binddn
and 
.B credentials
and should only be used when adequate security services
(e.g. TLS or IPSEC) are in place.
.B REMEMBER: simple bind credentials must be in cleartext!
A
.B bindmethod
of
.B sasl
requires the option
.B saslmech.
Depending on the mechanism, an authentication identity and/or
credentials can be specified using
.B authcid
and
.B credentials.
The
.B authzid
parameter may be used to specify an authorization identity.
Specific security properties (as with the
.B sasl\-secprops
keyword above) for a SASL bind can be set with the
.B secprops
option. A non default SASL realm can be set with the
.B realm 
option.
The identity used for synchronization by the consumer should be allowed
to receive an unlimited number of entries in response to a search request.
The provider, other than allowing authentication of the syncrepl identity,
should grant that identity appropriate access privileges to the data
that is being replicated (\fBaccess\fP directive), and appropriate time
and size limits.
This can be accomplished by either allowing unlimited \fBsizelimit\fP
and \fBtimelimit\fP, or by setting an appropriate \fBlimits\fP statement
in the consumer's configuration (see \fBsizelimit\fP and \fBlimits\fP
for details).

The
.B keepalive
parameter sets the values of \fIidle\fP, \fIprobes\fP, and \fIinterval\fP
used to check whether a socket is alive;
.I idle
is the number of seconds a connection needs to remain idle before TCP 
starts sending keepalive probes;
.I probes
is the maximum number of keepalive probes TCP should send before dropping
the connection;
.I interval
is interval in seconds between individual keepalive probes.
Only some systems support the customization of these values;
the
.B keepalive
parameter is ignored otherwise, and system-wide settings are used.

The
.B starttls
parameter specifies use of the StartTLS extended operation
to establish a TLS session before Binding to the provider. If the
.B critical
argument is supplied, the session will be aborted if the StartTLS request
fails. Otherwise the syncrepl session continues without TLS. The
.B tls_reqcert
setting defaults to "demand", the
.B tls_reqsan
setting defaults to "allow", and the other TLS settings
default to the same as the main slapd TLS settings.

The
.B suffixmassage
parameter allows the consumer to pull entries from a remote directory
whose DN suffix differs from the local directory. The portion of the
remote entries' DNs that matches the \fIsearchbase\fP will be replaced
with the suffixmassage DN.

Rather than replicating whole entries, the consumer can query logs of
data modifications. This mode of operation is referred to as \fIdelta
syncrepl\fP. In addition to the above parameters, the
.B logbase
and
.B logfilter
parameters must be set appropriately for the log that will be used. The
.B syncdata
parameter must be set to either "accesslog" if the log conforms to the
.BR slapo\-accesslog (5)
log format, or "changelog" if the log conforms
to the obsolete \fIchangelog\fP format. If the
.B syncdata
parameter is omitted or set to "default" then the log parameters are
ignored.

The
.B lazycommit
parameter tells the underlying database that it can store changes without
performing a full flush after each change. This may improve performance
for the consumer, while sacrificing safety or durability.
.RE
.TP
.B olcUpdateDN: <dn>
This option is only applicable in a replica
database.
It specifies the DN permitted to update (subject to access controls)
the replica.  It is only needed in certain push-mode
replication scenarios.  Generally, this DN
.I should not
be the same as the
.B rootdn 
used at the provider.
.TP
.B olcUpdateRef: <url>
Specify the referral to pass back when
.BR slapd (8)
is asked to modify a replicated local database.
If multiple values are specified, each url is provided.

.SH DATABASE-SPECIFIC OPTIONS
Each database may allow specific configuration options; they are
documented separately in the backends' manual pages. See the
.BR slapd.backends (5)
manual page for an overview of available backends.
.SH OVERLAYS
An overlay is a piece of
code that intercepts database operations in order to extend or change
them. Overlays are pushed onto
a stack over the database, and so they will execute in the reverse
of the order in which they were configured and the database itself
will receive control last of all.

Overlays must be configured as child entries of a specific database. The
entry's RDN must be of the form
.B olcOverlay={x}<overlaytype>
and the entry must have the olcOverlayConfig objectClass. Normally the
config engine generates the "{x}" index in the RDN automatically, so
it can be omitted when initially loading these entries.

See the
.BR slapd.overlays (5)
manual page for an overview of available overlays.
.SH EXAMPLES
.LP
Here is a short example of a configuration in LDIF suitable for use with
.BR slapadd (8)
:
.LP
.RS
.nf
dn: cn=config
objectClass: olcGlobal
cn: config
olcPidFile: LOCALSTATEDIR/run/slapd.pid
olcAttributeOptions: x\-hidden lang\-

dn: cn=schema,cn=config
objectClass: olcSchemaConfig
cn: schema

include: file://SYSCONFDIR/schema/core.ldif

dn: olcDatabase=frontend,cn=config
objectClass: olcDatabaseConfig
objectClass: olcFrontendConfig
olcDatabase: frontend
# Subtypes of "name" (e.g. "cn" and "ou") with the
# option ";x\-hidden" can be searched for/compared,
# but are not shown.  See \fBslapd.access\fP(5).
olcAccess: to attrs=name;x\-hidden by * =cs
# Protect passwords.  See \fBslapd.access\fP(5).
olcAccess: to attrs=userPassword  by * auth
# Read access to other attributes and entries.
olcAccess: to * by * read

# set a rootpw for the config database so we can bind.
# deny access to everyone else.
dn: olcDatabase=config,cn=config
objectClass: olcDatabaseConfig
olcDatabase: config
olcRootPW: {SSHA}XKYnrjvGT3wZFQrDD5040US592LxsdLy
olcAccess: to * by * none

dn: olcDatabase=mdb,cn=config
objectClass: olcDatabaseConfig
objectClass: olcMdbConfig
olcDatabase: mdb
olcSuffix: "dc=our\-domain,dc=com"
# The database directory MUST exist prior to
# running slapd AND should only be accessible
# by the slapd/tools. Mode 0700 recommended.
olcDbDirectory: LOCALSTATEDIR/openldap\-data
# Indices to maintain
olcDbIndex:     objectClass  eq
olcDbIndex:     cn,sn,mail   pres,eq,approx,sub

# We serve small clients that do not handle referrals,
# so handle remote lookups on their behalf.
dn: olcDatabase=ldap,cn=config
objectClass: olcDatabaseConfig
objectClass: olcLdapConfig
olcDatabase: ldap
olcSuffix: ""
olcDbUri: ldap://ldap.some\-server.com/
.fi
.RE
.LP
Assuming the above data was saved in a file named "config.ldif" and the
ETCDIR/slapd.d directory has been created, this command will initialize
the configuration:
.RS
.nf
slapadd \-F ETCDIR/slapd.d \-n 0 \-l config.ldif
.fi
.RE

.LP
"OpenLDAP Administrator's Guide" contains a longer annotated
example of a slapd configuration.

Alternatively, an existing slapd.conf file can be converted to the new
format using slapd or any of the slap tools:
.RS
.nf
slaptest \-f ETCDIR/slapd.conf \-F ETCDIR/slapd.d
.fi
.RE

.SH FILES
.TP
ETCDIR/slapd.conf
default slapd configuration file
.TP
ETCDIR/slapd.d
default slapd configuration directory
.SH SEE ALSO
.BR ldap (3),
.BR ldif (5),
.BR gnutls\-cli (1),
.BR slapd.access (5),
.BR slapd.backends (5),
.BR slapd.conf (5),
.BR slapd.overlays (5),
.BR slapd.plugin (5),
.BR slapd (8),
.BR slapacl (8),
.BR slapadd (8),
.BR slapauth (8),
.BR slapcat (8),
.BR slapdn (8),
.BR slapindex (8),
.BR slapmodify (8),
.BR slappasswd (8),
.BR slaptest (8).
.LP
"OpenLDAP Administrator's Guide" (http://www.OpenLDAP.org/doc/admin/)
.SH ACKNOWLEDGEMENTS
.so ../Project
